Presenters: Ohad Fremder Assaf Haim

Projects Goal  To detect the presence of a working cellular device within a confined room.  To locate the cellular device within the confined space at a 0.5x0.5m accuracy.

Solution Steps  Build pre unit.  Build one full unit.  One system builds from three units.  Placed the systems is the room (four systems).  Connect the systems to a computer.  Assumptions: There will be only one cellular device in the room, there will be no other RF in that room

General overview  We placed four systems with in the room (two on each side wall).  Each system consists of three basic units  Every unit is built of a dipole isotropy antenna, filters, gains, mixers, sum, energy detector.

Basic Unit Basic Unit schema: Filter Bank of Filters Mixer s Gains E.D su m

Pre Unit  In order to build the entire system we need to build a basic unit for a specific device. H.Pass 1.7Ghz Antenna L.Pass 1.9Ghz 20db L.O 1.5Ghz Mixer 26db Energy Detector L.Pass 400Mhz -1db -7db -1db 20db

Pre system  The pre system is the key to solve the problem.  We build the system wire up, therefore each component will be on "Print" ready for connection.  For testing purposes we use a VCO to simulate a cellular device.  The VCO and the mixer are the main components in the system therefore we designed them in separately.

VCO And Mixer Schema: GND IF LO RF Mixer SRA-220 V.C.O POS db RFout V-Tune Vcc 1 GND 1 3 2,5,6,

VCO Pin View: POS-2000A

VCO  Operating DC voltage at 8V.  To make sure that the power source is stable we used capacitors.  To protect the Mixer from returning signals we applied 3dB loss in its input, for that we designed a pie net resistors and placed it in the VCO output.  We need different values for Vtune so we use a 24V source with a potentiometer.  To view/test the frequency, as a result of Vtune we placed a test point.  To map the frequency output values Vs Vtune we conducted an experiment.

VCO Experiment  Motivation: The experiment has two main purposes. Check power and frequency in output/test point. To examine the frequency output values Vs Vtune.

VCO Experiment Schema: OutTest Spectrum Analyzer 8V24 V 50 Ohm VCO-POS2000 POWER

VCO Experiment  Conclusions and recommendations: VCO worked as expected. There is difference in power output between the datasheet to the actual value. (result of wire and connector losses) The difference between test pin to the output pin is - 21dB. When needed to know the output frequency you can measure Vtest with a spectrum analyzer. If Vtest is not used, connection of a resistor of 50 ohm is preferred.

Mixer Schema: Mixer SRA-220 2,5,6,

Finishing steps for the basic unit  Prepare the filters and gains for wire up.  Build (schema in page 19) an energy detector and an antenna.  Connect all the devices and conduct an experiment when the VCO is simulating the cellular device.  Sum the results and conclusions.

Full system schema: Antenna -1dB 26dB Energy Detector L.Pass 400Mhz H.Pass 800Mhz L.Pass 900Mhz 20dB L.O 1.15Ghz Mixer -1dB -7dB 20dB H.Pass 1.7Ghz L.Pass 1.9Ghz 20dB L.O 1.5Ghz Mixer -1dB -7dB 20dB sum 3

Future plans  Build the test case described in the Basic Unit.Basic Unit  Test the partial design.  Create 1 directional antenna.  Test the complete circuit including a directional antenna and 3 basic units.  Build the system CPU interface.  Test the system.